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Abstract:

Systems and methods for the delivery and monitoring of a medication, such
as insulin, to a recipient are provided. An exemplary feature-rich system
comprises an infusion pump with a control system for controlling
medication delivery by the infusion pump and a bolus estimator for
estimating an appropriate amount of medication for delivery by the
control system with the infusion pump. Estimating the appropriate amount
of medication for delivery is based upon one or more settings which each
vary according to a setting profile. In other embodiments, the control
system comprises a suspend function for temporarily suspending medication
delivery by the infusion pump, an alarm profile function for programming
a variable alarm volume of the alarm and a simplified menu for
controlling the dual wave bolus delivery function.

Claims:

1. A system for delivering medication, comprising: an infusion pump; a
control system for controlling medication delivery by the infusion pump;
and a bolus estimator for estimating an appropriate amount of medication
for delivery by the control system with the infusion pump, wherein:
estimating the appropriate amount of medication for delivery is based
upon one or more settings that include insulin sensitivity and vary
according to one or more setting profiles that can be set by a user to
vary according to a daily schedule; the control system controls
medication delivery according to one or more medication delivery profiles
comprising the appropriate amount of medication estimated by the bolus
estimator; and the setting profile is entered with a graphical
programming interface.

2. The system of claim 1, wherein the insulin sensitivity setting can be
set to vary according to a plurality of separate setting profiles that
are stored in a memory of the system.

3. The system of claim 1, wherein the control system includes a suspend
function for temporarily suspending medication delivery by the infusion
pump.

4. The system of claim 1, wherein the one or more settings further
include target blood glucose or carbohydrate ratio.

5. The system of claim 4, wherein the setting profile for at least one of
the one or more settings includes a value which varies according to a
schedule.

6. The system of claim 1, wherein the control system is programmed to
control medication delivery from a source selected from the group
including an RF programmer, a communication station and direct input.

7. The system of claim 1, wherein the bolus estimator estimates the
appropriate amount of medication based upon one or more event markers
stored in a memory of the system.

8. The system of claim 7, wherein the one or more event markers track
events which affect medication need.

9. The system of claim 7, wherein the one or more event markers are
selected from the group comprising a meal marker, a snack marker, a high
blood glucose marker, a low blood glucose marker, an exercise marker, an
illness marker and a stress marker.

10. The system of claim 1, wherein the graphical programming interface
includes a moveable indicator element that is used to select a setting
profile that the user wishes to modify.

11. A method of delivering medication, comprising the steps of:
controlling medication delivery by an infusion pump with a control
system; estimating an appropriate amount of medication for delivery by
the control system with the infusion pump, wherein: estimating the
appropriate amount of medication for delivery is based upon one or more
settings that include insulin sensitivity and vary according to one or
more setting profiles that can be set by a user to vary according to a
daily schedule; the control system delivers medication delivery according
to one or more medication delivery profiles comprising the appropriate
amount of medication estimated by the bolus estimator; and the setting
profile is entered with a graphical programming interface.

12. The method of claim 11, wherein the insulin sensitivity setting can
be set to vary according to a plurality of separate setting profiles that
are stored in a memory of the system.

13. The method of claim 12, wherein the one or more medication delivery
profiles includes the appropriate amount of medication estimated by the
bolus estimator.

14. The method of claim 12, wherein the one or more settings further
include target blood glucose or carbohydrate ratio.

15. The method of claim 14, wherein the setting profile for at least one
of the one or more settings includes a value which varies according to a
schedule.

16. The method of claim 11, wherein the control system is programmed to
control medication delivery from a source selected from the group
including an RF programmer, a communication station and direct input.

17. The method of claim 11, wherein the bolus estimator estimates the
appropriate amount of medication based upon one or more event markers
stored in a memory of the system.

18. The method of claim 17, wherein the one or more event markers track
events which affect medication need.

19. The method of claim 17, wherein the one or more event markers are
selected from the group comprising a meal marker, a snack marker, a high
blood glucose marker, a low blood glucose marker, an exercise marker, an
illness marker and a stress marker.

20. The method of claim 11, wherein the graphical programming interface
includes a moveable indicator element that is used to select a setting
profile that the user wishes to modify.

[0003] This invention relates generally to systems for delivering and
monitoring medications. More specifically, this invention relates to
methods and systems for the infusion of insulin.

[0004] 2. Description of the Related Art

[0005] Infusion devices and systems are well-known in the medical arts for
delivering or dispensing a medication to a patient, such as insulin to a
diabetic. Generally such devices include a reservoir containing a
medication for administration to the patient, an infusion pump for
dispensing a medication (typically through infusion tubing and an
associated catheter) and control and monitoring systems to facilitate the
accurate delivery of the medication.

[0006] Infusion pumps typically include a small drive motor connected to a
reservoir piston to administer the medication to the user. Programmable
controls can be provided for operating the drive motor continuously or at
periodic intervals to obtain a closely controlled and accurate delivery
of the medication over an extended period of time. Exemplary infusion
pumps that are used to administer insulin and other medications are shown
and described in U.S. Pat. Nos. 4,562,751; 4,678,408; 4,685,903;
5,080,653 and 5,097,122, and U.S. patent application Ser. No. 09/334,858,
filed Jun. 16, 1999, entitled "EXTERNAL INFUSION DEVICE WITH REMOTE
PROGRAMMING BOLUS ESTIMATOR AND/OR VIBRATION ALARM CAPABILITIES", all of
which are incorporated herein by reference.

[0007] Infusion devices provide significant advantages over manual
administration by accurately delivering insulin or other medications over
an extended period of time. Infusion devices can be relatively compact as
well as water resistant, and may thus be adapted to be carried by the
user, for example, by means of a belt clip. As a result, medication can
be delivered to the user with precision and in an automated manner,
without significant restriction on the user's mobility or lifestyle,
including the ability to participate in water sports.

SUMMARY OF THE INVENTION

[0008] Embodiments of the invention disclosed herein provide monitors and
delivery systems which allow for the an enhanced control of the delivery
of a medication. A typical embodiment of the present invention includes
an infusion pump, a control system for controlling medication delivery
from the infusion pump and a bolus estimator for estimating an
appropriate amount of a medication such as insulin or the like for
delivery by the control system via the infusion pump, where estimating
the appropriate amount of the medication for delivery is based upon one
or more settings which can be varied according to a setting profile. For
example, a control system can control medication delivery according to
one or more medication delivery profiles. In preferred embodiments,
medication delivery profiles are designed to optimize the delivery of an
appropriate amount of insulin that is estimated by the bolus estimator.
Such medication delivery profile settings can include additional settings
relating to factors such as target blood glucose, carbohydrate ratio
and/or insulin sensitivity. In one embodiment, the setting profile for at
least one setting, such as target blood glucose, carbohydrate ratio or
insulin sensitivity, includes a value which varies according to a
schedule.

[0009] In preferred embodiments of the invention, the bolus estimator
estimates the appropriate amount of insulin based upon one or more event
markers stored in a memory of the device. The one or more event markers
can track physiological events which affect insulin need, such as meals,
medication status, activities or general health. Such embodiments can
include a wide variety of markers such as a meal marker, a snack marker,
a high blood glucose marker, a low blood glucose marker, an exercise
marker, an illness marker and/or a stress marker.

[0010] Another embodiment of the invention includes a control system for
controlling medication delivery from the infusion device. Such control
systems can be tailored to the requirements of a specific pathology. In
an illustrative embodiment, a control system includes a suspend function
for temporarily suspending medication delivery from the infusion device.
In preferred embodiments of the invention, medication delivery is
controlled using two or more medication delivery profiles, such as wave
profiles. Exemplary wave profiles include a square wave bolus profile, a
dual wave bolus profile or a basal profile. In a preferred embodiment of
the invention, the control system includes a suspend function for
separately suspending medication delivery based on the wave profiles. In
another embodiment, the control system further includes a resume function
for selectively restarting a wave profile. In such systems, a
compensating function can also be used for delivering a compensating
bolus to account for any suspended wave profile. The suspend function can
further include a full suspend function for directly suspending all
delivery of a medication.

[0011] In yet another embodiment of the invention, the suspend function
includes a menu system for selecting a period of time for temporarily
suspending medication delivery from the infusion pump. The menu system
can include, for example, an array of fixed periods from which to select
a period of time for temporarily suspending medication delivery. In
preferred embodiments, the menu system can also include one or more
selectable increment periods to modulate the period of time for
temporarily suspending medication delivery. In another embodiment, the
menu system includes a specified time of day to select as an end of the
period of time for temporarily suspending medication delivery. In some
embodiments of the invention, after a period of time for temporarily
suspending medication delivery has concluded, the pump automatically
resumes medication delivery.

[0012] In a related embodiment of the invention the suspend function
includes a block function for preventing delivery of medication after a
potentially harmful amount of medication is requested by a user. The
potentially harmfully amount of medication can result, for example, from
a request for an unusually large bolus, a bolus requested too soon after
a previous bolus is delivered, or, alternatively, a request for too low
of a total medication dose. Such functions typically include a warning
signal to the user of the potentially harmful amount of medication
requested. In one embodiment, the block function can be triggered in
situations where a medication measurement that is integrated over an
integration period (e.g., the period of time in which a measured amount
of medication is infused) exceeds a target value. In another embodiment,
the block function can be triggered in situations where a second
medication measurement that is integrated over a simultaneous and
overlapping integration period exceeds a target value. The integration
period can further be subdivided into a plurality of subperiods where
each subperiod is associated with a subtotal representing medication
delivered. In one embodiment of the invention, the oldest subtotal of the
subperiods can be replaced by the newest subtotal of the subperiods to,
for example, identify a possible overmedication.

[0013] In yet another embodiment of the invention the infusion pump
includes an alarm to provide information on the status of the infusion
pump and a control system for controlling medication delivery from the
infusion pump. For example, the control system can include an alarm
profile function for programming a variable alarm volume of the alarm. In
one embodiment, the variable alarm volume can be set by the user. In a
related embodiment, the alarm profile function varies the alarm volume
according to a preselected schedule.

[0014] Another embodiment of the invention includes an infusion pump and a
control system for controlling medication delivery by the infusion pump
including a dual wave bolus delivery function, where the control system
includes a conventional menu for controlling the dual wave bolus delivery
function (e.g., a menu identifying parameters associated with a wave
bolus delivery function which may be set by the user). In a related
embodiment, the control system includes a conventional or simplified menu
for controlling the dual wave bolus delivery function (e.g., a menu
identifying one or more preset parameters associated with a dual wave
bolus). Embodiments of the invention include those where the simplified
menu and the conventional menu can be alternately selected. In preferred
embodiments of the invention, the simplified menu includes a single entry
of a total medication volume that can be divided by a preset ratio into a
first wave bolus and a second wave bolus and then delivered with a preset
delay time between the first wave bolus and the second wave bolus. In
other preferred embodiments of the invention, the preset ratio and preset
delay time can include default values set in a pump setup menu. The
control system can also include one or more additional delivery functions
and a default delivery mode selected in the pump setup menu from the dual
wave bolus delivery function and/or the additional delivery functions
disclosed herein. Examples of such delivery functions include a square
wave bolus delivery function and a basal delivery function.

[0015] In preferred embodiments of the invention, the control system is
programmed to control medication delivery from an RF programmer, a
communication station and/or direct manual input. In another embodiment
of the invention, a first device of an infusion device and RF remote pair
can be used to find the second device by activating a find function in
the first device to induce an audible signal from the second device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Referring now to the drawings in which like reference numbers
represent corresponding parts throughout:

[0017] FIG. 1 is a block diagram of an exemplary infusion device
embodiment of the invention;

[0018]FIG. 2 is a block diagram of the infusion device configured through
a communication station;

[0025] Embodiments of the present invention encompass methods and systems
for the convenient operation of medication infusion devices. The
description provided herein encompasses the architecture of the
apparatus, associated features which optimize the control and convenience
of such devices and methods for their utilization. Features which
optimize the control and convenience of the devices of the present
invention may be implemented in a wide range of infusion device designs
known in the art.

[0026] A typical embodiment of the present invention includes an infusion
pump, a control system for controlling medication delivery from the
infusion pump and a bolus estimator for estimating an appropriate amount
of a medication such as insulin or the like for delivery by the control
system via the infusion pump. In preferred embodiments, a function of
estimating the appropriate amount of the medication for delivery is based
upon one or more settings (e.g., a variable parameter that can be used to
control the delivery of a medication) which can be varied according to a
setting profile (e.g., a prescribed relationship between the setting and
a variable, such as another setting or a schedule). Typically, the
control system controls medication delivery according to one or more
medication delivery profiles (e.g., setting profiles for a medication
delivery rate that varies according to a schedule). In preferred
embodiments the medication delivery profiles are designed to optimize the
delivery of an appropriate amount of insulin that is estimated by the
bolus estimator. In highly preferred embodiments, the setting profile for
at least one setting, such as target blood glucose, carbohydrate ratio or
insulin sensitivity, includes a value that varies according to a
schedule. In other preferred embodiments of the invention, the bolus
estimator estimates the appropriate amount of insulin based upon one or
more event markers stored in a memory of the device (e.g., the
recordation of when a earlier bolus was administered).

[0027] FIG. 1 illustrates a typical infusion device 100 of the present
invention. A processor 102 contained in a housing 104 of the device 100
controls the operation of the infusion device 100. The processor 102,
connected to internal memory 106, can be used to run programs that
control the infusion device 100. The memory 106 stores programs,
historical data, user defined information, settings and other parameters.
In one embodiment the memory can be a flash memory and SRAM. In
alternative embodiments, the memory 106 may include other memory storage
devices such as ROM, DRAM, RAM, EPROM, and dynamic storage such as other
flash memory and magnetic media and similar devices. In one embodiment
the infusion device 100 can be programmed directly through a manual input
device 108, such as a keyboard or touch screen input, built directly into
the device. The device 100 can include (or alternatively include)
programmability through commands received from a radio frequency (RF)
programmer 110 through an RF transceiver 112 built into the device 100.
Feedback from the device 100 on the status or programming changes are
displayed on a display 114, such as an liquid crystal display (LCD) or
touch screen display, and/or audibly through a speaker 116. The RF
programmer typically includes an input device of some type, such as a
simple keypad, and may also include a display and/or speaker to provide
feedback in a manner similar to the infusion device 100.

[0028] In preferred embodiments of the invention, the processor 102 can be
coupled to a drive mechanism 118 that can be connected to a medication or
fluid reservoir 120 containing fluid that can be directed through an
outlet 122 in the reservoir 120 and housing 104, and then into a body of
a user through tubing and an infusion set 124. In other embodiments, the
input device 108, display 114 and/or speaker 116 can be omitted from the
external infusion device 100, with all programming and data transfer
being handled through the RF programmer 110. In further embodiments, the
infusion device 100 can deliver fluid directly to the user without tubing
or an infusion set 124. For example, the infusion device 100 can be
located on the user's body at the infusion site.

[0029] In an illustrative embodiment of the invention, the infusion device
100 can be a medication infusion pump capable of delivering insulin to a
diabetic at a rate of about 0 to about 35 units/hour in basal rates and
up to about 25.0 units per meal bolus of U-100 insulin. In related
embodiments, the infusion pump delivers other concentrations of insulin
and/or other medications and may operate at other rates. Alternative
embodiments of the invention can deliver other fluid compositions such as
saline, as well as fluids that include agents such as vitamins,
medications, drugs, peptides, hormones, proteins, enzymes, and vaccines,
or the like.

[0030] The external infusion device 100 can provide the user with an alarm
signal as a warning to indicate some situation to address such as a low
reservoir condition or low battery or some malfunction of the system
(e.g., an occlusion of the outlet that restricts the delivery of the
fluid). In one embodiment of the invention, the user has the choice of an
audible alarm through the speaker 116 and/or a vibration alarm 126.
Alarms may start out at a low level and escalate until acknowledged by
the user. In further embodiments, both an audible alarm and a vibration
alarm 126 may be given at the same time.

[0031] Embodiments of the invention can also include a bolus estimator 128
which may operate as an independent unit within the device or as a
program run by the processor 102. The bolus estimator 128 can function as
a specialized calculator, providing values for estimating the insulin
needs of the patient and simplifying the management of the administration
of insulin to the patient. For example, some settings for the bolus
estimator 128 are a target blood glucose value, units of blood glucose
measurement (e.g., mmol/l or mg/dl), units of carbohydrate, the
carbohydrate to insulin ratio, insulin sensitivity and blood glucose
lockout (a block, requiring a minimum time delay before the bolus may be
adjusted to allow the previous estimate to act).

[0032] In embodiments of the present invention, profiles can be applied to
a wide range of settings to facilitate versatile control of the infusion
device 100. Numerous settings govern control of the infusion device. Some
settings are directed to the actual administration of medication, such as
the delivery rate, blood glucose level, carbohydrate to insulin ratio or
insulin sensitivity. Other settings direct more mundane aspects of the
operation of the infusion device, such as alarm volume. Any infusion
device setting can be controlled according to a profile. A setting that
uses a profile can vary according to at least one other condition or
input. For example, a setting can operate by a profile that varies in
value according to a daily schedule. In this case, the other condition is
time. Profiles can be used to vary the medication delivery rates (e.g.,
medication delivery profiles), which can be described as waves. Although,
schedule-based setting profiles are preferred, setting profiles can also
be used which vary according to other settings, such as blood glucose
(BG) or carbohydrate measurements.

[0033] Medication delivery by the infusion device 100 is preferably
managed through the use of profiles which represent a varying medication
delivery rate over a fixed period of time. Multiple programming options
can be available in the infusion device 100, and preferably includes at
least two customized basal profiles, a carbohydrate (or bolus) estimator
128 and an alarm clock, as well as remote and/or on-device programming.

[0034]FIG. 2 is a block diagram of the infusion device configured through
a communication station 130. A physician/educator can configure the
external infusion device 100 through a communication station 130 to
provide or restrict access to certain programming options. In preferred
embodiments, an external infusion device 100 can download stored
information through the communication station 130. A description of a
communication station of this general type is found in U.S. Pat. No.
5,376,070 to Purvis et al., entitled "DATA TRANSFER SYSTEM FOR AN
INFUSION PUMP" and U.S. Pat. application Ser. No. 09/409,014, filed Sep.
29, 1999 (PCT publication WO 00/18449) to Malave et al., entitled
"COMMUNICATION STATION AND SOFTWARE FOR INTERFACING WITH AN INFUSION
PUMP, ANALYTE MONITOR, ANALYTE METER OR THE LIKE", which are both
incorporated herein by reference. Such information can be used alone or
in combination with information from a glucose sensor and/or a glucose
meter (not shown) to assist the user and/or the health care professional
in making intelligent therapy decisions. Moreover, the information,
programs and data may be downloaded to a remote or local PC, laptop,
communication station, or the like, for analysis and review by trained
professional through the transceiver 112. The data may also be downloaded
through a communication station 130 to a remotely located computer 132
such as a PC, laptop, or the like, over communication lines 134, such as
by wired, modem, wireless connection or other electronic communication
methods.

[0035] Operation of the infusion device 100 is typically directed through
programming which can be derived from a variety of possible sources. The
programming can either be entered directly into the infusion device 100
(e.g., on the input device 108), received via the RF programmer 110, or
transferred from the communication station 130 (originating, for example,
in the computer 132). In one embodiment, the infusion device maintains an
event log in the memory 106 that includes the source of programming. This
information can be used to study trends in the use of the infusion device
100 as well as to quickly diagnose the source of flawed programming.

[0036] The external infusion device 100 can also have additional memory
capacity to allow configuring of the display during manufacturing to
display information in several different foreign languages, and allow for
future upgrades and revisions without the requirement of a hardware
change. For example, a PC program can enable manufacturing to select the
language for the pump. Languages can include English, French, Spanish,
Italian, Dutch, Swedish and German. In alternative embodiments, other
languages can be determined based upon market selection.

2. Bolus Estimator

[0037] Physiological carbohydrate levels are a predominant, but not
exclusive factor affecting blood glucose levels. The bolus estimator 128
of the invention (or carbohydrate estimator that estimates a bolus based
on carbohydrate consumption (CHO)) can assist the user with carbohydrate
counting and in determining precise dosing adjustments to account for
meals. Generally, it is sufficient to account just for the carbohydrates.
It also encourages the user to enter current blood glucose values before
using this feature, which increases compliance with medical regimens and
optimizes control of medical devices. In certain embodiments of the
invention, the bolus estimator 128 in the external infusion device 100
can be connected or coupled to a glucose monitor by way of the RF
programmer 110 (or other data transfer mechanism) to provide direct input
to the bolus estimator 128.

[0038] In preferred embodiments of the invention, the bolus estimator 128
is used to assist the external infusion device 100 user with the
estimations to determine the proper bolus amount needed to cover an
anticipated carbohydrate intake at meals. The bolus estimator 128 can
effect this by suggesting a bolus based on a pre-programmed carbohydrate
ratio that can be stored in the memory 106 of the external infusion
device 100. The bolus estimator 128 can also take into account the user's
insulin sensitivity and the differential between the user's
pre-programmed target blood glucose (BG) level and the user's current BG
level at the time the carbohydrate estimator 128 is activated. In this
context, the recommendation, or result of the bolus estimator 128, is
sometimes referred to as a "correction bolus".

[0039] The bolus estimator 128 is generally activated by the user or the
health care professional in a setup menu of the external infusion device
100, before it is operational, and preferably after the user has
demonstrated a sufficient understanding of how to estimate carbohydrate
intake. In preferred embodiments, the bolus estimator 128 is activated
and programmed by using the input device 108 on the external infusion
device 100. In some embodiments, the bolus estimator 128 may be
alternately programmed and activated with an RF programmer 110. In other
embodiments, the current glucose readings for the user can be provided by
receipt of the medication level measurement from a glucose monitor or via
the RF programmer 110 to facilitate a correction for changing blood
glucose (BG) levels. Descriptions of correcting infusion rates based on
blood glucose readings may be found in U.S. Pat. No. 5,569,186 to Lord et
al., entitled "CLOSED LOOP INFUSION PUMP SYSTEM WITH REMOVABLE GLUCOSE
SENSOR,"; U.S. Pat. No. 5,665,065 to Colman et al., entitled "MEDICATION
INFUSION DEVICE WITH BLOOD GLUCOSE DATA INPUT"; and U.S. patent
application Ser. No. 09/334,858, filed Jun. 16, 1999 and entitled
"EXTERNAL INFUSION DEVICE WITH REMOTE PROGRAMMING BOLUS ESTIMATOR AND
VIBRATION ALARM CAPABILITIES"; which are all herein incorporated by
reference.

[0040] In alternative embodiments of the invention, the user may be able
to use other combinations of the values to identify different bolus types
and amounts. In other embodiments, the bolus estimator 128 can be used in
a closed-loop system to augment the readings or check the closed-loop
system's capability based on carbohydrate estimated meals. In other
embodiments, the bolus estimator 128 may be used to calculate correction
boluses based on other parameters, with the type of bolus corrections
being determined by the medication being infused, physiological
characteristics of the user or the like. Preferably, the bolus estimator
128 uses stored values or parameters related to the individual and
current values, parameters or measurements applied to an algorithm to
provide a recommended bolus that can be accepted, modified or rejected by
the user. For instance in situations of premature labor in pregnancy, the
measurement of the contraction rate may be used to suggest a bolus of
tocolysis medication. In HIV, a bolus amount of medication being infused
may be adjusted based on a relationship to the current viral loads in the
patient. In stroke or cardiac cases, the coagulation rate may be used to
determine the bolus amount of heparin to be administered. Other
calculations may be made and the invention is not limited to the
above-described examples.

[0041] After the bolus estimator 128 has been enabled, the user can be
prompted to store values for the following properties in the memory 106
of the external infusion device 100: the target blood glucose, insulin
sensitivity and the carbohydrate ratio. In alternative embodiments, more
or fewer properties may be needed or used by the bolus estimator 128.
These values are used by the bolus estimator 128 and the processor 102 of
the external infusion device 100 to perform the necessary calculations in
suggesting a bolus amount. In preferred embodiments, access to
programming and changing these values may be restricted to a health care
professional. In other embodiments, these values can be restricted to
entry through an RF programmer 110 or a connection of the external
infusion device 100 with a programming device, such as a PC, laptop or
the like. Examples of inputted values to be stored for the bolus
estimator 128 are provided below.

[0042] Target blood glucose (Target) is the target blood glucose (BG) that
the user would like to achieve and maintain. Generally, the programmable
blood glucose (BG) values for this range are between 60 to 200 in
five-unit increments. Preferably, the carbohydrate calculator has the
capability to accept values that; range between 20 to 600 in 1-unit
increments to cover a large number of possible scenarios. In alternative
embodiments, different ranges and increments may be used.

[0043] Insulin sensitivity (Set Sens) is a property that reflects how far
the user's blood glucose drops in milligrams per deciliter (mg/dl) when
one unit of insulin is taken. Typically, the programmable values for this
range are between 5 to 180 in one unit increments. However, in
alternative embodiments, different ranges and increments may be used. In
other embodiments, insulin sensitivity can be programmable for multiple
different time periods (e.g., up to four different periods), the use of
which can require multiple separate profiles to be stored in the memory
106. Setting the Insulin sensitivity profiles can be similar to setting
the basal profiles. In alternative embodiments, more or fewer time
periods (and corresponding profiles) may be used.

[0044] The carbohydrate ratio (Set Carbs) is a value that reflects the
amount of carbohydrates that are covered by one unit of insulin.
Generally, the values are in the range of 1 to 300 in increments of 1
unit (or, alternatively, in ranges of 0.1 to 5.0 in increments of 0.1 for
carbohydrate exchanges). Preferably, the programmable values for this
range are between 5 to 30 in one unit increments. However, in alternative
embodiments, different ranges and increments can be used.

[0045] As a safety precaution, the user or healthcare professional may
also set a Lockout Period, which takes into account the pharmacokinetic
effect of insulin when suggesting a bolus. The purpose is to prevent a
successive use of a correction bolus when the pharmacokinetic effects of
the previous bolus have not yet been accounted for. The programmable
values for this range are between 30 minutes to 240 minutes, programmable
in 15 or 30 minute increments. However, in alternative embodiments,
different ranges and increments may be used. In further alternative
embodiments, the lock out period may be automatically calculated based on
boluses recently delivered and/or canceled based on new blood glucose
(BG) readings. In other embodiments, the carbohydrate calculator 118 may
include a programmable reminder to check the post-prandial blood glucose
value to determine if additional boluses and or corrections should be
made at a later time after the meal. The programmable reminder values are
between 30 minutes to 240 minutes, programmable in 15 or 30 minute
increments. In alternative embodiments, different values and increments
may be used.

[0046] After the properties are set in the memory 106 of the external
infusion device 100, the bolus estimator 128 can suggest a bolus based on
the entry of the estimated carbohydrate intake and current and target
blood glucose (BG) levels. The calculation can be performed using the
three properties programmed and stored in the memory 106. Preferred
embodiments use the following equation:

[0047] In contexts where the user wishes the external infusion device 100
to suggest a bolus for the estimated carbohydrate intake only, then the
only value to program is the carbohydrate ratio, and the BG portion of
the equation can be ignored. In alternative embodiments, variations or
different equations can be used.

[0048] In operation, once the bolus estimator 128 has been enabled and the
above listed values have been programmed into the memory 106 of the
external infusion device 100, the bolus estimator 128 can be used to
suggest a correction or meal bolus. The user may then accept or change
the bolus amount suggested by the bolus estimator 128. In one embodiment,
processor 102 stores in memory 106 a record of whether the suggested
bolus amount from the bolus estimator 128 was accepted or changed by the
user, and records the suggested and changed bolus amounts. The stored
data can be used for later analysis by downloading the data to a computer
by wired, RF or IR transmissions, for example by IR transmissions from
the external infusion device 100 through a communication station to the
computer, or the like as previously described.

[0049] Some embodiments of the invention employ a normal bolus. In
alternative embodiments, the user may be given the choice of a normal,
dual, square wave bolus, extended bolus, profiled bolus, or the like, by
enabling these capabilities on the variable bolus menu in the setup menu
on the external infusion device 100. If the variable bolus capability is
not enabled, then every bolus would be a normal bolus. Preferred
embodiments of the present invention use normal one-time boluses.
However, alternative embodiments may utilize different bolus types to
spread out the correction or meal bolus determined by the bolus estimator
128.

[0050] Since the external infusion device 100 stores the time of each
bolus delivery, simple algorithms as illustrated above can be designed to
take into account the amount of insulin that might still be remaining in
the user's body from a previous bolus. The longer the programmed time for
the "Insulin Duration Factor" then the more conservative the estimate
becomes. In other embodiments, the external infusion device 100 can
adjust for several boluses that were delivered within the insulin
duration window. Although it is difficult to absolutely predict how long
insulin will actually remain active in the body, the above-described
algorithm does at least consider the effects on the amount of insulin
actually needed. This provides an additional level of conservative
estimation in the external infusion device 100 by accounting for insulin
delivered within a programmable window. Without such an algorithm, the
infusion device 100 could suggest a larger bolus than required because
the remaining insulin might not have been accounted for in the suggested
bolus.

[0051] The bolus estimator 128 has the advantage of prompting the user to
enter his/her blood glucose (BG) value, and thus also serves as a useful
reminder to check BG levels regularly. This makes testing more
advantageous, since the results directly assist the user in maintaining
control of the patient's condition. Also, the bolus estimator 128 enables
the external infusion device 100 to capture information on carbohydrate
intake which is valuable for helping the user to refine carbohydrate
counting skills. This data may also be downloaded to a PC, laptop,
communication station, RF programmer, or the like and applied to programs
to provide an advanced analysis of the patient's insulin needs.

[0052] In other embodiments, an external infusion device 100 and user can
utilize the bolus estimator 128 information to "learn" insulin
sensitivity values, carbohydrate counting, the effects of high fat meals
and other variables that can lead to better control, and use this to
adjust the results of the bolus estimator 128. In alternative
embodiments, the user can omit entering specific carbohydrate amounts
each time calculations are made by the user. For example, the external
infusion device 100 may store the carbohydrate amounts for several meals
that are regularly eaten by the user in the memory 106, and then allow
the user to recall the stored meals. In other alternative embodiments, a
list of general foods to may be provided with a carbohydrate equivalent.
In other embodiments, the external infusion device 100 may utilize a more
complicated keypad and/or RF programmer 110, and a code can be assigned
for each food. Then the code for each food to be consumed can be entered
into the external infusion device 100.

[0053]FIG. 3A illustrates how the settings 300 of the bolus estimator 128
may be fixed or variable. One or more of these settings (e.g., the
carbohydrate ratio, target blood glucose and insulin sensitivity), can
follow a profile that changes over the course of a day. FIG. 3A shows
example profiles for the carbohydrate ratio 302 and insulin sensitivity
304 values that vary over a daily schedule. Using these profiles enables
the bolus estimator 128 to provide a more accurate estimate of the
appropriate amount of insulin for a patient at a given moment. Different
profiles can also be used for different days. In general, profiles can be
generated to account for the anticipated activities of the patient which
affect the medication needs of the patient. For example, a workday
profile may be different than a weekend day profile. Days during which
the patient plans to exercise can have a different profile than days
spent at rest. In addition profiles can also be created for different
lengths of time. For example, a weeklong profile can be created around a
patient's default routine. Short duration profiles to accommodate
unplanned activities can then be inserted as necessary.

[0054] The bolus estimator 128 can store values of current BG,
carbohydrates to be consumed and the estimated and actual bolus size and
type which can be used to provide valuable information to the user. This
data of the bolus estimator 128 can be used to develop an understanding
of how time of day and other global effects should be accounted for in
using the estimator 128. For example, the data can be used to calculate
improved values for the carbohydrate ratio and the insulin sensitivity.
The data accumulated by the estimator includes a record of insulin
delivery as well as blood glucose measurements.

[0055] FIGS. 3B-3D illustrate a graphical programming interface for
setting profiles. In some embodiments of the invention, profiles can be
set using a convenient and efficient graphical interface. Using the
interface a profile description 306 is shown in graphical form. The
description 306 is composed of a series of discrete setting divisions for
the particular parameter being programmed. The user begins by moving an
indicator (e.g., a flashing division) from one end of the profile
description 306 until he arrives at the first division 308 in the profile
that he wishes to modify. At this division, the user indicates (e.g.,
using an up and down arrow selector) the desired value for the particular
first division 308. In response, the interface automatically applies an
identical value to the subsequent division in the profile description
306. In other words, each following division is set at the same level as
the adjusted division. See FIG. 3B. Following this the user begins to
move the indicator to the next division 310 that he wishes to adjust from
the setting of the first division 308. All intervening divisions will
retain the setting of the first division 308. See FIG. 3B. This division
310 is now adjusted and again all subsequent divisions are adjusted to
match. Prior divisions in the profile, however, remain unchanged from the
setting of the first division 308. As shown in FIG. 3D, the process can
be repeated by moving the indicator onward and setting subsequent
divisions (e.g., division 312). Because the user is not required to enter
a setting for every division in the profile description, the graphical
interface enables a user to quickly enter a desired profile without
tedious and repetitive effort. In addition the graphical interface can
also display the time, setting value or rate and total for the programmed
profile. It should be noted that this graphical interface can be used for
setting any parameter that uses a profile (e.g., carbohydrate ratio,
insulin sensitivity as well as bolus profiles which will be detailed
hereafter).

[0056] FIGS. 4 and 5 illustrate, respectively, exemplary daily detail and
summary screens for bolus estimator use and carbohydrate intake in an
analysis program. FIG. 4 illustrates daily summaries of carbohydrate and
medication intake. FIG. 5 illustrates detailed carbohydrate, glucose and
insulin information for a single day. Use of the bolus estimator can also
be tracked in the detail and summary screens. This information can be
used to monitor patient use of the bolus estimator as well as improve the
accuracy of the bolus estimator function.

[0057]FIG. 4 illustrates a daily summary report screen. This report
provides a summary of information relating to the glucose data status and
insulin data status for a particular day. Alternatively, it may provide a
report for several days in a summary format as shown. The glucose data
status section shows the number of readings, the average glucose value
and the range. The insulin data status section shows total amount of
insulin taken, the number of boluses, the number of bolus estimates, the
carbohydrate use, the prime volume, the percent of the time that a
temporary basal rate was used, and the percent of time that the infusion
pump operation was suspended.

[0059] Carbohydrate intake is graphically shown in the upper section and
indicates when and how much carbohydrate consumption has occurred. The
graph is derived from carbohydrate consumption events (such as indicated
by meal or snack markers) from the event marker table that have been
logged by the user. The event markers can be logged into the pump and
stored for later downloading or entered directly into the running
software program. The exemplary event marker table is shown in the upper
side section of the report screen and is further detailed below.

[0060] The infusion pump data is shown in the middle section and
graphically depicts basal rate, bolus, prime, and alarm history for the
specified day. The basal rate is shown as a line indicating: normal basal
rate, temporary basal rate, auto-off, and suspend (e.g., the programmed
normal basal rate can be shown as a dashed line during any of: suspend,
temporary basal rate, or auto-off). Boluses delivered can also be
indicated. The alarm markers will be positioned to show the time of any
alarm. In the illustrated report, two insulin scales are marked due to
the relative scale of a bolus (large) compared to a basal rate (small).
The bolus scale shall be on the left y-axis and the basal scale shall be
on the right hand y-axis. In particular embodiments, any priming events
will also be shown. Pie chart data is shown in a lower side section and
graphically depicts basal:bolus ratio and bolus type as pie charts.

[0061] The sensor and meter data is shown in the lower section and
graphically depicts meter readings and sensor data -vs.- time for the
specified day. Any continuous glucose monitor (i.e., sensor) readings can
be displayed as a continuous line graph. Meter readings can be marked as
either a reference value or as calibration points. Any sensor event
markers, such as small rectangular markers, or the like, at the bottom
edge shall depict sensor event markers.

[0062] The alarm/event/marker table is shown in an upper side section and
will be shown only if either infusion pump, glucose meter, glucose
monitor (i.e., sensor) or carbohydrate consumption data are present.
Alarms and events from the infusion pump, glucose meter and glucose
monitor can be listed in order of time of the event/alarm. Textual
definitions for events shall be listed if defined; otherwise a numeric
value for the events shall be shown. For example, the table can display
the following events involving programming changes for the current day:
Time/Date change--displays new date (in mm-dd-yy format) and new time,
where the time change is displayed in either 12 or 24 hr format depending
on user's settings; Suspend On/Off--time the feature was turned on and
was time turned off; Temporary basal rate--displays setting of a
Temporary Basal Rate including amount in units per hour (e.g. 0.6 u/h)
and duration displayed in same format as duration for bolus history;
Basal Rate change--a note referring to a Basal Profile section for basal
rate change history; battery removal/replacement--displays the removal
and subsequent replacement of batteries with time of action; Maximum
Basal Rate change--changes of the setting along with the time of action;
Maximum Bolus change--displays the change of setting along with the time
of action; Insulin Concentration change--displays the change of
concentration; Auto Off Change--displays new feature setting along with
the time of change displayed in hours; Alarm/Error Code--brief
description of the alarm/error.

[0063] Furthermore, a variety of additional event markers can be stored in
the event log in the memory 106 of the infusion pump. Markers can
identify any significant events (beyond mere programming changes) which
relate to the administration of medication to a particular patient and
can be useful in improving dosage estimating. For example, a meal marker
can identify a significant carbohydrate intake and a snack marker can
identify a less significant intake. Any range of markers indicating a
range of carbohydrate intake values can be used. Markers can also be used
to indicate low or high BG values. Exercise, illness and stress, which
also affect appropriate medication dosage, can also be tracked with event
markers. At least some of these events can be taken as inputs to the
bolus estimator 128 in calculating an insulin dosage. In this way the
bolus estimator can provide a complex analysis of insulin need in
real-time for the patient based upon the most current readings an
estimates of BG values. For example, the infusion device 100 can track BG
values and insulin use along with the number of hypo- and hyper-
medication readings, as well as the patient response to high or low BG.
In addition, the event log can be downloaded to be used in other analysis
software to identify broader trends which can be used to improve the
bolus estimator 128 predicative abilities for a particular patient. Thus,
event markers can be used in conjunction with the pump memory (e.g., the
memory of the bolus estimator 128) and glucose data (e.g., from a glucose
sensor and meter) to provide specific and average pre- and post-event
analysis. Embodiments of the present invention provide a convenient way
to accumulate accurate event data by capturing the information directly
in the pump.

[0064] Similar to the setting profiles (e.g., carbohydrate ratio and
insulin sensitivity), medication can be delivered through the infusion
device according various profiles which vary over time. For example a
basal profile represent a base level of insulin which is delivered over a
period of time. Various bolus profiles can also be used in response to
more immediate needs of the patient, such as from eating a meal. Some
examples of bolus profiles include a square wave and a dual wave profile.
The infusion device can be programmed to deliver insulin according to
various profiles. Details of the operation of an exemplary infusion
device are provided in U.S. patent application Ser. No. 09/334,858, filed
Jun. 16, 1999, which is incorporated by reference herein.

[0065] Although dual wave bolus delivery provides a good match to a user's
need, the number of operations required to employ the dual bolus (as well
as other advanced infusion device operations) may limit it use by some
patients. To address this, embodiments of the present invention employs
simplified dual wave bolus programming. Dual wave bolus programming is
activated through a menu presented to the user.

[0066] In one embodiment of the invention, the user enters the total
desired insulin volume and that volume is divided into the two portions
of the dual wave bolus, the immediate and the delayed portions, by a
predefined ratio. The ratio may be fixed as a preselected setting or
adjustable as a user setting. In a further embodiment, the delay time
between the immediate and delayed portions is also predefined by a user
setting. For example, a delay of 1-1/2 hours can be defined at the
factory.

[0067] In another embodiment, the delivery bolus profile (e.g., dual wave,
square or other) can be set such that one form can be used by default.
This eliminates the need for the user to specify the bolus profile every
time.

[0068] In yet another embodiment, the user can select the level of
programmability with respect to the dual wave bolus. A setting of full
programmability can allow/require the user to program all aspects of the
dual wave bolus per a traditional menu as initially described. A setting
of a lower level of programmability can require some values to be input
directly (e.g. the ratio between the immediate and delayed portions)
while other values (e.g. the delay time) are taken from stored values.
The lowest level of programmability merely requires entry of the total
desired insulin volume; other required values are taken from stored
preselected settings. Thus, with only one entry, a dual bolus can be
delivered.

[0069] It should be understood that although simplified bolus programming
is described here with respect to programming a dual wave bolus,
simplified bolus programming can be applied to any bolus profile
including square wave bolus profiles.

3. Convenience Features

[0070] Other embodiments of the invention can employ a suspend function
which automatically delivers a "take a break bolus" to allow a patient to
disconnect from the infusion device 100 for a predetermined period. This
function is particularly well adapted for short acting medications. The
purpose of this capability is to deliver an extra bolus before
disconnecting from the external infusion device 100 to make certain that
the needed amount of medication is delivered before interrupting the
administration. This can help the user remain above the minimum
therapeutic level during an interruption of medication delivery.
Preferably, four durations of an interruption of the medication infusion
are used: 30 minutes; 1 hour; 1 hour and 30 minutes; and 2 hours.
However, additional, or longer or shorter intervals may be used.
Generally, this capability is activated in the setup menu by the health
care specialist, who can program the dose for each of the possible times
of delivery interruptions. The dose is set based on the medication and
the condition of the user. If the health care specialist programs only
certain durations (for example, 30 minutes and 1 hour only), the user
will only be able to take a break for those durations. In alternate
embodiments, the user can set the break duration and associated dosages.
In preferred embodiments, in the "take a break bolus" menu screen, the
user can program the duration of the planned interruption. The external
infusion device 100 can then beep after the delivery of the previously
set dose. The user can then disconnect from the external infusion device
100 and can be reminded by the external infusion device 100 to reconnect
when the time is up. Preferably, the reminder alarm can continue to sound
(or vibrate) until the user reactivates the external infusion device 100.
In alternate embodiments, the infusion device has a dedicated button,
touch-screen button or other method, for the user to activate a "take a
break" bolus.

[0071] Other embodiments of the invention can use a more versatile suspend
function. For example, FIG. 6 is a flowchart illustrating a suspend
function embodiment of the invention. Upon selecting the suspend
function, the user is presented with a menu to select the period for
suspension. In one embodiment, predetermined intervals (e.g., 1/2 hour, 1
hour, 2 hours, etc.) are presented to be selected as described above. In
another embodiment, as illustrated in FIG. 6, the suspend duration can be
incremented by a predetermined amount (e.g., 15 minute or 30 minute
intervals under the "SET BASAL DELAY" menu) and then entered. Also as
illustrated in FIG. 6, in yet another embodiment, the user may specify a
particular time (e.g., 12:13 PM under the "SET RESUME BASAL TIME" menu)
for the pump to resume operation. The appropriate "take a break bolus"
can be determined as a function of the selected time based upon settings
provided in the setup menu.

[0072] The infusion device 100 also allows for selective suspension of
specified functions. The infusion device can be programmed to deliver at
a rate defined by a basal profile or in a bolus. A bolus can be delivered
all at once and it can also be spread over a period, such as with the
square wave or dual wave profiles. The delivery profiles can also be
simultaneously programmed into the infusion device. In this case, when a
user wishes to suspend operation of the infusion device, the user can be
given the option of activating a complete suspension or selecting which
profile(s) to suspend. For example, if the user has programmed the
infusion device to deliver a bolus and then changes his mind, the user
may want to immediately suspend the bolus (e.g., square or dual wave),
but may want to maintain the basal delivery rate. In another example, the
user may want to suspend delivery of the basal profile, but maintain
delivery of a bolus profile.

[0073] In addition, when the user restarts the infusion device 100 after a
suspended operation the user can select which profiles are to be resumed
and how they shall be resumed. In one embodiment, the user can select to
resume a suspended square wave or dual wave bolus to restart at the point
it was suspended. In another embodiment, the user can select to restart
the basal profile. In another embodiment, the user may also select that
the restarting the infusion device includes calculation and delivery of a
compensating bolus to account for the fluid missed as a result of the
suspended operation.

[0074] It is also important that suspending the operation of the infusion
device does not require multiple operations in an emergency. Therefore a
dedicated button or key can be provided to directly cause full suspension
of all pump delivery. The selective suspend functions previously
discussed are accessed through a separate menu. A warning signal can be
provided through the speaker if a suspend function is enabled to indicate
the operation status to the user. In addition, the dedicated suspend key
can call up the suspend menu for further selections by the user.

[0075] Embodiments of the present invention also allow the alarm volume to
be programmed according to a profile. In one embodiment, the user can
select different volume levels for different time periods of the day. For
example, the user may select a low volume level from 8 AM to 10 PM and a
high volume level from 10 PM to 8 AM. Of course, any number of periods
and multiple volume levels can be used. This aspect of the invention
enables users to have a desired alarm volume at a desired time without
having to manually change the volume setting daily.

4. Safety Features

[0076] Embodiments of the present invention include a variety of safety
features that assist in preventing misuse of the infusion device.
Warnings, such as a screen displaying full circles, symbols, messages,
color changes, flashing, a special font style, or other means used to get
the user's attention, can be used to inform the user of a potentially
unsafe condition. Such warnings can be used for conditions including, low
battery voltage, an empty or low reservoir, excessive bolus requests, an
unusually large bolus request and the like.

[0077] In addition, from time to time the user can temporarily remove the
infusion device. It is important that the infusion device is not
misplaced. Using the RF remote, embodiments of the present invention
allow the user to readily identify the location of the infusion device by
activating a transmitter in the remote and cause the infusion device,
receiving the signal, to emit an audible signal through the speaker.
Furthermore, the RF remote can be equipped with a speaker and, by the
same principle, the infusion device can trigger the RF remote to issue an
audible signal so that the user can quickly locate the RF remote. Using
either of these "find functions" of the infusion device and RF remote
pair, the user can quickly locate one device with the other.

[0078] In other embodiments a "lockout function" can be included to
restrict operation of the infusion device 100. Preferred embodiments can
have multiple lockout levels, with the selection dependent upon the
anticipated usage, the external infusion device model, the sophistication
of the user, or the like. For example, the following lockout levels can
be used. A lockout level means that some of the features of the external
infusion device may not be accessible to the patient (or user), but will
be accessible to the health care professional or the parent of a child
using the external infusion device 100. Access control can be managed by
requiring a password or some other authentication method. A lockout level
of "None" (0) can let the user program and access all features of the
external infusion device 10. A lockout level of "Setup" (1) can generally
lock the user out of changing the setup menu parameters. The user may
only have access to activated features of the external infusion device
100, but can not change the pre-set parameters. The user will be able to
review the settings, and only change the lockout level with an
authorizing key sequence. The only setup feature that will still be
available is selftest. A lockout level of "All except Suspend" (2) can
only allow the user to suspend the external infusion device and to
perform a selftest. All other features can be locked out. The user can be
able to review the settings, and only change the lockout level with an
authorized key sequence. Finally, the "Lockout function" can be accessed
in the setup menu. A special key sequence (or code) can be required to
change the lockout level. This can minimize the possibility of an
unauthorized change of the lockout levels. In preferred embodiments, an
icon (lock) can be displayed on the display 114 when the external
infusion device 100 is in lockout mode 1 or in lockout mode 2.

[0079] Preferred embodiments of the external infusion device 100 can
include a configurable menu that can be accessible by password through
the use of a PC, laptop, RF programmer or the like. This ability allows
the physician, or sophisticated user, to select only the external
infusion device 100 capabilities that are required for an individual
user. A "lock out" capability can enable the physician to exclude certain
options from the user. This may be useful with new users or children
using the external infusion device 100.

[0080] In another embodiment, a user can enable a block function that
limits the operation of the infusion device. The block function can be
employed in situations where the patient must be supervised in using the
infusion device, such as when the patient is a child or very elderly and
there is a risk that they will inadvertently misuse the infusion device
and possibly harm themselves. Enabling the block function limits the
maximum bolus delivery in some fashion. For example, in one embodiment,
the maximum bolus dose and/or the maximum basal rate are limited. The
block function can also be set to operate by a predetermined schedule.
For example, the block function may operate during a period when
operation of the infusion device will be regularly unsupervised, such as
when a child is at school.

[0081] In preferred embodiments, there can be a maximum number of external
infusion device 100 strokes for the drive mechanism 118 that may occur in
one hour based on the maximum basal rate and bolus amounts. Typically,
the external infusion device 100 can sound (and/or vibrate) and the
external infusion device 100 will not be able to deliver more than
((2.5*maximum bolus)+maximum basal+1) strokes in one hour. Preferably,
the external infusion device 100 will deliver medication in 0.1 units
volume increments (although other increments may be used). The actual
amount of insulin or medication in a given stroke depends on the insulin
or medication concentration, stroke length and delivery reservoir
diameter or cross-sectional area. In preferred embodiments, the delivery
rates are scrolled by the amount of insulin per stroke. The rate delivery
pattern can be calculated by dividing the number of strokes required for
the rate into 3600 (the number of seconds in one hour). The result is the
number of seconds between each stroke. The rate can be delivered evenly
over the hour, each stroke on a one-second boundary. Rates that do not
divide evenly into 3600 will not have any accumulating error. For
example, consider a rate of 3.0 units per hour and a concentration of
U-100 3.0 U/hr at U-100 will require 30 strokes per hour. This translates
to a pump stroke every 3600/30=120 seconds, or one stroke every two
minutes. In alternative embodiments, the drive mechanism 118 may provide
for continuous flow rather than incremental or pulsed flow rates. Further
alternatives may omit strokes and utilize hydraulics, pneumatics, step
motors, continuous motors, or the like.

[0082] The suspend and/or block functions can be triggered by monitoring
the amount of infused medication. The amount of infused medication can be
determined by integrating the pump rate over a period of time. The pump
rate can be measured by the active delivery profiles (basal, square wave
bolus, dual wave bolus, etc.). The monitored period (e.g., at one hour
intervals) continuously repeats itself, comparing the accumulated total
to a target limit derived from a maximum basal and maximum bolus limit.

[0083] In one embodiment of the invention, more than one integration can
be simultaneously performed at staggered and overlapping intervals.
Without such multiple integration operations, a potentially harmful
amount of medication could still be delivered if its delivery spans two
integration periods.

[0084] FIGS. 7A-7C illustrate integration plots for triggering the block
function. FIG. 7A illustrates the integration plot 700 of the infusion
rate that repeats after a fixed period. If a preselected target level
(e.g., a specific over-infusion amount of insulin based on a maximum
bolus and maximum basal rate) 702 is exceeded within any single period
704, the block function can be enabled. FIG. 7B illustrates integration
plots 700 where the target level 702 is not exceeded in the first or the
second period because the integration is restarted at the beginning of
the second period. It can be seen from the extended line 706 that the
target level would have been exceeded if medication delivery had been
integrated over an alternate single period 708. FIG. 7c illustrates two
repeating staggered and overlapping integration plots 700, 710. The two
plots are integrated over equivalent periods 704, 708 that are out of
phase with each other. For example, the periods can be 1-hour long and 30
minutes out of phase with each other. A potentially harmful dose, which
would have escaped detection using only the first integration plot 700,
is now detected by the second overlapping integration plot 710.

[0085] It should be understood that staggered and overlapping integration
periods are equivalently implemented by shortening the integration period
and storing the final total from the previous integration period. The
stored value can be added to the current integration and the total can be
checked against the target. This is true because two simultaneous
integration plots produce the same change in their respective medication
totals. In effect, embodiments of the invention can divide the full
monitored period into two integration subperiods

[0086] The full monitored period can be subdivided into multiple
integration subperiods, each concluding with a final subtotal
representing the medication delivered over each subperiod. The system
stores the final subtotals of the multiple integration periods. As each
new integration period is concluded, the new total replaces the value of
the oldest stored subperiod.

[0087] The optimum number of subperiods (i.e. the subperiod size) to use
can be determined by proposing a hypothetical subperiod size and
determining the total amount of medication that could possibly be
delivered by the infusion device during the hypothetical period (based
upon the maximum delivery capacity of the infusion device, for instance).
If this amount can be acceptably ignored as it is replaced as the oldest
subtotal, the subperiod size is acceptably small.

[0088] In addition, embodiments of the invention can also improve
performance of block function triggering by synchronizing the integration
periods with infusion device operation. For example, the pump may ignore
any period of negligible infusion prior to beginning a significant
medication infusion. The integration period can be initiated when a
sudden change in infusion is detected. In this way, monitoring for the
block function can be appropriately synchronized with higher infusion
rates.

[0089] In another embodiment of the invention, the target level is based
upon an analysis of actual infusion device use for a given patient that
is incorporated into the infusion device. This dynamic target level can,
for example, be based upon a historic daily average (e.g. over a week or
10 days) of the maximum count of infused medication for an integration
period for each day. An appropriate margin can be added to the historic
daily average to obtain the dynamic target level from the historic daily
average. In such embodiments of the invention, the infusion device stores
values of the maximum count of medication delivered in an integration
period of each day. If, in a given integration period, a total amount of
an infused medication exceeds the dynamic target level, the suspend
and/or block functions can be invoked. This dynamic target level and
associated monitoring provides the benefit of tracking changes in
infusion use over time. For example, a weight change of the patient that
causes a gradual increase or decrease in insulin use can gradually alter
the dynamic target level.

[0090] In preferred embodiments of the invention, this dynamic target
level is used instead of a typical fixed target level (e.g. one based
strictly upon a fixed maximum bolus and/or maximum basal infusion rate).
In specific embodiments of the invention, the user can select between a
dynamic target level and a fixed target level. For example, in contexts
where a sufficient number of days of history have not yet accumulated so
as to yield a meaningful daily average, the dynamic target level can be
superseded (even if selected) in favor of a fixed target level until a
such history is established.

[0091] The historic daily average, upon which the dynamic target level is
based, can be maintained in the infusion device memory and adjusted at
the conclusion of each day by formulae such as the following:

T i = T i - 1 ( N - 1 ) + G N ##EQU00002##

where, Ti is the new daily average, Ti-1 is the previous daily
average, N is the number of days of historic use and G is the new maximum
medication count. An appropriate margin (e.g., up to 3 standard
deviations or a percentage of the daily average) is added to the new
daily average to determine the new dynamic target level. For example, the
new dynamic target level can be simply set at 20% over the daily average.
Alternately, embodiments of the invention can calculate a standard
deviation value from the historic use to determine an appropriate margin
to add to the new daily average and determine the new dynamic target
level. For example, the new target level can be the new daily average
plus three standard deviations.

[0092] As can be observed from the equation above, the number of days of
historic use of the medication delivery system (N) influences the
determination of the dynamic target level. In this context, the selection
of N influences the responsiveness of the dynamic target level to more
recent changes in infusion use. An average level from a fewer number of
days produces a dynamic target level that changes quickly in response to
recent use. In contrast, as the number of days of historic use is
increased, the dynamic target level is more stable and less affected by
possibly anomalous recent fluctuations in medication use. In such
situations, a balance can be struck between the desired responsiveness of
the delivery device and stability in the selection of the appropriate
number of days of historic use. In addition, calculating a new dynamic
target level the invention can disregard medication counts for days
during which a previous dynamic target level was exceeded.

[0093] The foregoing description including the preferred embodiments of
the invention has been presented for the purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed. Many equivalent modifications
and variations are possible in light of the above teaching.

[0094] It is intended that the scope of the invention be limited not by
this detailed description, but rather by the claims appended hereto. The
above specification, examples and information provide a complete
description of the manufacture and use of the apparatus and method of the
invention. Since many embodiments of the invention can be made without
departing from the scope of the invention, the invention resides in the
claims hereinafter appended. Throughout the specification various patents
and other references are cited. The disclosures of these are incorporated
by reference in their entirety.

Patent applications by Cary Dean Talbot, Saugus, CA US

Patent applications by Denetta Malave, Valencia, CA US

Patent applications by Leif N. Bowman, Livermore, CA US

Patent applications by Mark C. Estes, Simi Valley, CA US

Patent applications by MEDTRONIC MINIMED, INC.

Patent applications in class Applied for interferential effect in body

Patent applications in all subclasses Applied for interferential effect in body